High-rise buildings typically contain a number of elevators, escalators and other corresponding traveling means for transporting people from one floor to another in the building. When a passenger gives calls to the elevators, the group control of the elevator system allocates an elevator in the elevator system to the passenger's use on the basis of the prevailing traffic situation and the given optimization criteria. The giving of calls in a conventional elevator system is arranged by disposing up/down pushbuttons on each floor, by means of which the passenger expresses his/her desired direction of travel and further, after the elevator has reached the floor on which the passenger is located, the passenger expresses his/her desired destination floor by means of the destination floor pushbuttons in the elevator car. The method of giving calls described above is, however, impractical and often inefficient, as a result of which the giving of calls in elevator systems is implemented to an increasing extent by means of a so-called destination call system, in which the passenger gives his/her personal destination floor information already at the departure floor, e.g. in the entrance lobby before going into the elevator car. The giving of a destination call takes place by means of a special destination call terminal, either with pushbuttons and/or by means of an electrically readable identifier, e.g. an RFID (radio frequency identifier) tag. Since in connection with a destination call the departure point and terminal point of the travel route of each passenger is identified and therefore available to the group control, the group control is able to determine the travel route of a passenger precisely and optimally compared to a conventional call-giving system.
The objective of allocating calls given by passengers is to assess the different route options for passengers and to give the calls to be served to the elevators in such a way that some performance indicator or a combination of performance indicators describing the elevator system is as good as possible. Conventionally the most commonly used performance indicators are performance indicators relating to the service times of a passenger but optimization criteria relating to energy or to another corresponding property of the elevator system are also possible. A so-called cost function is generally used to compare route options with each other, the minimization of the value (total cost) of which cost function with different route options expresses the optimal allocation. The allocation can also be implemented such that a suitable cost function for the best traffic situation at that time is taken into use in different traffic situations. This is to give the elevator system the opportunity to adapt to the prevailing traffic situation, e.g. upward peak traffic in a building. The technique in question is described in patent publication FI972937, among others, from where a control method of an elevator group is known in which the control of the elevators is optimized on the basis of the traffic situation, i.e. the traffic type and the traffic intensity prevailing at any given time, in which case the prevailing traffic situation is identified and the elevator group is controlled on the basis of the optimization criteria corresponding to the aforementioned traffic situation. In order to identify the prevailing traffic situation, statistical information is collected about the use of the elevator system according to different 24-hour periods and days of the week, and the future traffic situation of the elevator system is forecast at any given moment in time on the basis of the statistical data collected. The solution in question is called a traffic forecaster.
The elevator systems of buildings are typically long-term investments, which from time to time must be modernized in situations in which they no longer meet the requirements set for the traffic arrangements of the building. The reason for modernization can be e.g. a substantial increase in maintenance costs owing to the obsolescent elevator technology of the elevator systems, or it is possible that the usage of the building has changed and the transport capacity of the elevator systems is not sufficient for transporting the increased number of passengers in the building. It is also usual that changes occurring in the safety aspects and/or in the official regulations of the elevator systems influence modernization decisions.
Modernization projects are by nature demanding projects, which can last months, in certain cases even years, if the entire installed base of elevators of the building must be modernized. Owing to this an essential objective attached to the modernization of elevator systems is maintaining the transport capacity of the elevator systems during the modernization phase. So that the transport capacity is disturbed as little as possible during the modernization, it is attempted to implement the modernization in stages, e.g. by modernizing one elevator of the elevator group at a time in each stage. During modernization it is therefore typical that some of the elevators of an elevator group are modernized and some are unmodernized, with the shared use of which the elevator passengers must be served. For the coordination and shared use of the modernized and unmodernized elevators to be efficient, in some prior-art modernization solutions the group control of an elevator group is replaced with a new group control immediately in the initial stage of the modernization work. The new group control is connected in this case to the elevator controls that are to be modernized by means of special adapter units such that the calls given by passengers can be allocated in the new group control to both unmodernized and modernized elevators and the control commands according to the allocation result can be transmitted to each elevator via the aforementioned adapter units. One such prior-art modernization solution is presented in Finnish patent publication FI98362, in which a new group control as well as new elevator-specific elevator controls are temporarily connected to the old elevator controls by means of special adapter units. The elevator group is modernized by function modules by integrating the functionalities and/or the function modules to be modernized into a new group control and/or into new elevator controls and by removing the corresponding functions from the old elevator controls until all the modernization procedures are done and the temporary adapter units as well as the old elevator controls can be removed from the elevator group. Another prior-art solution is disclosed in publication U.S. Pat. No. 6,935,465, in which the aforementioned destination call system is utilized in connection with modernization. In the solution in question in the starting stage of the modernization work the old elevator controls in the elevator group are connected using special adapter units to the new group control and also destination call panels are installed on the floor levels for receiving destination calls given by passengers. The new group control allocates elevators from the elevator group on the basis of destination calls given by the passengers and if an elevator allocated to a passenger is an unmodernized elevator, the new group control transmits control commands according to the destination call via the aforementioned adapter unit to the old elevator control of the allocated elevator. One prior-art modernization solution is also presented in publication U.S. Pat. No. 5,389,748, in which a new group control as well as a special adapter computer (ITM) is connected to the elevator system to be modernized, wherein the landing calls given by passengers are divided to the old group control and to the new group control in the desired ratio. In the solution in question the old landing appliance bus together with the landing call appliances are removed and replaced with new landing call appliances and also a new landing appliance bus, which is connected to the aforementioned adapter computer. To transmit the landing calls to the group controls, the adapter computer is connected to an interface of the landing appliance bus of both the new and the old group control.
One problem with prior-art modernization solutions is that when replacing an old group control of an elevator group with a new group control it is necessary during the initial stage of the modernization to arrange interfaces (a so-called overlay) between the new group control and the old elevator controls. If the interface in question must be arranged in all the old elevator controls, the interface easily becomes complex and laborious to implement. Particularly in large elevator groups, the number of circuits needed can rise to be very high because the more elevators there are in the elevator group to be modernized the greater the number of connection points there are. As the number of circuits during the modernization increases, the costs of the modernization work as well as the probability of wrong connections rise, in which case the implementation becomes error-prone and the operating safety of the elevators can be jeopardized during the modernization. Often also it is necessary to tailor one-time functionalities for the adapter units and/or for the other systems required by the modernization, which functionalities are individual to the elevators of a certain manufacturer thereby, of course, increasing the modernization costs. In elevator systems in which signals between the group control and the elevator-specific controls or the landing appliances are transmitted through a manufacturer-specific data transfer protocol in serial format, the implementation of prior-art modernization solutions can be extremely laborious if not almost impossible. Special drives can also be connected to elevator systems that are to be modernized, e.g. fireman's drive, the implementation of which during modernization is typically awkward and can demand special arrangements during the modernization in order for e.g. a fireman's drive that is compliant with official regulations to be implemented and maintained in the elevator system to be modernized.